Recent content by cruff

Can you tack two wires to the leads of C5 so that you can measure it while in operation?

Don't assume that because a trace is tiny it can't carry a higher voltage. It is the current the trace carries that is the important factor in trace area (and thus width). Did you mean to say that C5+ pin is connected to the LM324M pins 3 and 10? What supply voltages are supplied to the op amp...

The metallic paint is there to reduce radio frequency interference generated by the IIsi, but with all the noise in the current environment from switching power supplies, etc, you may not notice any problems unless you are an amateur radio operator or you have one nearby. Looks like if it comes...

You might try a quick reheat of the pins for Y2 and the pins 12+13 on the 8530 just to see if it is a cold solder joint.

PCLK looks ok, that would be timing the access to the internal registers of the 8530. It looks like the frequency is correct (3.58 MHz), as the rest of the IIgs seems to be working. From the trace of the pin 13 RTxCA signal (and pin 32), it should be 3.6864 MHz, so should look similar in...

I hesitate to suggest replacing the chip unless we can understand what exactly the self test is failing on. Do you have access to an oscilloscope? You could verify if the the two clock signals (PCLK related to register access from the CPU) and the baud rate clock are working correctly. R2 is...

We've see this before, but haven't figured out what the cause is yet. According to a ROM source listing found at https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Computers/Apple%20II/Apple%20IIGS/Documentation/, the serial I/O chip test failure code 01 indicates a problem with...

Just remember that some nylon cable tie straps will degrade over a period of years due to heat or UV.

https://www.digikey.com/en/products/filter/rectangular-connectors-board-in-direct-wire-to-board/317?s=N4IgjCBcoEwBxVAYygMwIYBsDOBTANCAPZQDaIAzAJwBsVADBALqEAOALlCAMrsBOASwB2AcxABfQgFoYiECkj8ArgWJkQAVhBNxkkLMjkAkgBEAwtvFA

You'll need to determine their physical size, footprint, value in ohms, if they are linear (probably) or logarithmic taper, and the power dissipation needed in watts. Reviewing the schematics would give you at least ohms and possibly the wattage. Measurement of the PCB will determine the...

Look at the post referenced in the banner at the top of the page for the problems.

Ok, all I have is a crappy phone picture, I didn't get my good DSLR out to do a proper job. The moire pattern was caused by the phone sensor, and it doesn't look like that at all. The picture was quite good once I disabled the auto image scalling and increased the brightness setting. My...